diff --git a/core/modules/field/lib/Drupal/field/Plugin/views/field/Field.php b/core/modules/field/lib/Drupal/field/Plugin/views/field/Field.php
index f242dc0..30b0398 100644
--- a/core/modules/field/lib/Drupal/field/Plugin/views/field/Field.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/views/field/Field.php
@@ -51,7 +51,7 @@ class Field extends FieldPluginBase {
    *
    * @var \Drupal\Core\Field\FieldDefinitionInterface
    */
-  public $fieldDefinition;
+  protected $fieldDefinition;
 
   /**
    * The field config.